Three species of tern, Sable Island National Park Reserve

Three different species of tern on a sandy beach: Roseate tern, Arctic tern, and Common tern.

The closest bird is a Roseate tern, it stands with its beak agape, identifiable by its black beak and more slender body.

Behind that bird and slightly to the right is an Arctic tern, identifiable by its darker red beak.

Then behind both those birds and slightly to the left is a Common tern, whose beak also hangs open, identifiable by its orange beak and its heavier body.